Combined Heat Transfer in a Semitransparent Multilayer Packed Bed

Combined radiative, conductive, and forced convective heat transfer through a packed bed composed of two spectrally dissimilar slabs of particles is analyzed on the basis of the two-flux model. Taking into account the variation of absorption and scattering of the layers in the visible and infrared spectral ranges, the selectivity of such a system is proved theoretically. Experiments are run using a bed composed of glass and silicon carbide particles as a solar absorber for gas heating. Good agreement is shown in the comparison of predictions with experimental data.